clean up tail call transformer

lib/6to5/transformation/templates/tail-call-body.js

@@ -4,9 +4,11 @@
       SHOULD_CONTINUE_ID,
       RESULT_ID;
 
+  var CALLEE_ID = FUNCTION;
+
   do {
     SHOULD_CONTINUE_ID = false;
-    RESULT_ID = FUNCTION.apply(THIS_ID, ARGUMENTS_ID);
+    RESULT_ID = CALLEE_ID.apply(THIS_ID, ARGUMENTS_ID);
   } while(SHOULD_CONTINUE_ID);
 
   return RESULT_ID;

lib/6to5/transformation/transformers/es6/tail-call.js

@@ -43,9 +43,11 @@ function transformExpression(node, scope, state) {
           leftId,
           node.left
         );
+
         if (node.operator === "&&") {
           testExpr = t.unaryExpression("!", testExpr);
         }
+
         return [t.ifStatement(testExpr, returnBlock(leftId))].concat(callRight);
 
       case "SequenceExpression":
@@ -122,21 +124,17 @@ var functionChildrenVisitor = {
     if (t.isReturnStatement(node)) {
       // prevent entrance by current visitor
       this.skip();
+
       // transform return argument into statement if
       // it contains tail recursion
       return transformExpression(node.argument, scope, state);
     } else if (t.isFunction(node)) {
-      return this.skip();
+      this.skip();
     } else if (t.isTryStatement(parent)) {
       if (node === parent.block) {
-        return this.skip();
-      } else if (node === parent.finalizer) {
-        return;
-      } else {
-        if (parent.finalizer) {
-          this.skip();
-        }
-        return;
+        this.skip();
+      } else if (parent.finalizer && node !== parent.finalizer) {
+        this.skip();
       }
     }
   }
@@ -201,6 +199,7 @@ exports.FunctionExpression = function (node, parent, scope) {
     SHOULD_CONTINUE_ID: shouldContinueId,
     ARGUMENTS_ID:       argumentsId,
     RESULT_ID:          resultId,
+    CALLEE_ID:          scope.generateUidIdentifier("callee"),
     FUNCTION:           t.functionExpression(null, node.params, block),
     THIS_ID:            thisId,
   });

test/fixtures/transformation/es6-tail-call/call-apply/expected.js

@@ -1,27 +1,29 @@
-"use strict";
-
-(function f(n) {
-  var _arguments = arguments,
-      _this = this,
-      _shouldContinue,
-      _result;
-  do {
-    _shouldContinue = false;
-    _result = (function (n) {
-      if (n <= 0) {
-        console.log(this, arguments);
-        return "foo";
-      }
-      if (Math.random() > 0.5) {
-        _arguments = [n - 1];
-        _this = this;
-        return _shouldContinue = true;
-      } else {
-        _arguments = [n - 1];
-        _this = this;
-        return _shouldContinue = true;
-      }
-    }).apply(_this, _arguments);
-  } while (_shouldContinue);
-  return _result;
-})(1000000) === "foo";
+"use strict";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  var _callee = function (n) {
+    if (n <= 0) {
+      console.log(this, arguments);
+      return "foo";
+    }
+    if (Math.random() > 0.5) {
+      _arguments = [n - 1];
+      _this = this;
+      return _shouldContinue = true;
+    } else {
+      _arguments = [n - 1];
+      _this = this;
+      return _shouldContinue = true;
+    }
+  };
+
+  do {
+    _shouldContinue = false;
+    _result = _callee.apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000) === "foo";

test/fixtures/transformation/es6-tail-call/expressions/expected.js

@@ -1,30 +1,32 @@
-"use strict";
-
-(function f(n) {
-  var _arguments = arguments,
-      _this = this,
-      _shouldContinue,
-      _result;
-  do {
-    _shouldContinue = false;
-    _result = (function (n) {
-      var _left;
-      if (n <= 0) {
-        return "foo";
-      } else {
-        doSmth();
-
-        if (!(_left = getTrueValue())) {
-          return _left;
-        }
-        if (_left = getFalseValue()) {
-          return _left;
-        }
-        _arguments = [n - 1];
-        _this = undefined;
-        return _shouldContinue = true;
-      }
-    }).apply(_this, _arguments);
-  } while (_shouldContinue);
-  return _result;
-})(1000000, true) === "foo";
+"use strict";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  var _callee = function (n) {
+    var _left;
+    if (n <= 0) {
+      return "foo";
+    } else {
+      doSmth();
+
+      if (!(_left = getTrueValue())) {
+        return _left;
+      }
+      if (_left = getFalseValue()) {
+        return _left;
+      }
+      _arguments = [n - 1];
+      _this = undefined;
+      return _shouldContinue = true;
+    }
+  };
+
+  do {
+    _shouldContinue = false;
+    _result = _callee.apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000, true) === "foo";

test/fixtures/transformation/es6-tail-call/recursion/expected.js

@@ -1,23 +1,25 @@
-"use strict";
-
-(function f(_x, /* should be undefined after first pass */m) {
-  var _arguments = arguments,
-      _this = this,
-      _shouldContinue,
-      _result;
-  do {
-    _shouldContinue = false;
-    _result = (function (_x, m) {
-      var n = arguments[0] === undefined ? getDefaultValue() : arguments[0];
-      if (n <= 0) {
-        return "foo";
-      }
-      // Should be clean (undefined) on each pass
-      var local;
-      _arguments = [n - 1];
-      _this = undefined;
-      return _shouldContinue = true;
-    }).apply(_this, _arguments);
-  } while (_shouldContinue);
-  return _result;
-})(1000000, true) === "foo";
+"use strict";
+
+(function f(_x, /* should be undefined after first pass */m) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  var _callee = function (_x, m) {
+    var n = arguments[0] === undefined ? getDefaultValue() : arguments[0];
+    if (n <= 0) {
+      return "foo";
+    }
+    // Should be clean (undefined) on each pass
+    var local;
+    _arguments = [n - 1];
+    _this = undefined;
+    return _shouldContinue = true;
+  };
+
+  do {
+    _shouldContinue = false;
+    _result = _callee.apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000, true) === "foo";

test/fixtures/transformation/es6-tail-call/try-catch/expected.js

@@ -1,65 +1,69 @@
-"use strict";
-
-(function f(n) {
-  if (n <= 0) {
-    return "foo";
-  }
-  try {
-    return f(n - 1);
-  } catch (e) {}
-})(1000000) === "foo";
-
-(function f(n) {
-  var _arguments = arguments,
-      _this = this,
-      _shouldContinue,
-      _result;
-  do {
-    _shouldContinue = false;
-    _result = (function (n) {
-      if (n <= 0) {
-        return "foo";
-      }
-      try {
-        throw new Error();
-      } catch (e) {
-        _arguments = [n - 1];
-        _this = undefined;
-        return _shouldContinue = true;
-      }
-    }).apply(_this, _arguments);
-  } while (_shouldContinue);
-  return _result;
-})(1000000) === "foo";
-
-(function f(n) {
-  if (n <= 0) {
-    return "foo";
-  }
-  try {
-    throw new Error();
-  } catch (e) {
-    return f(n - 1);
-  } finally {}
-})(1000000) === "foo";
-
-(function f(n) {
-  var _arguments = arguments,
-      _this = this,
-      _shouldContinue,
-      _result;
-  do {
-    _shouldContinue = false;
-    _result = (function (n) {
-      if (n <= 0) {
-        return "foo";
-      }
-      try {} finally {
-        _arguments = [n - 1];
-        _this = undefined;
-        return _shouldContinue = true;
-      }
-    }).apply(_this, _arguments);
-  } while (_shouldContinue);
-  return _result;
-})(1000000) === "foo";
+"use strict";
+
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {
+    return f(n - 1);
+  } catch (e) {}
+})(1000000) === "foo";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  var _callee = function (n) {
+    if (n <= 0) {
+      return "foo";
+    }
+    try {
+      throw new Error();
+    } catch (e) {
+      _arguments = [n - 1];
+      _this = undefined;
+      return _shouldContinue = true;
+    }
+  };
+
+  do {
+    _shouldContinue = false;
+    _result = _callee.apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000) === "foo";
+
+(function f(n) {
+  if (n <= 0) {
+    return "foo";
+  }
+  try {
+    throw new Error();
+  } catch (e) {
+    return f(n - 1);
+  } finally {}
+})(1000000) === "foo";
+
+(function f(n) {
+  var _arguments = arguments,
+      _this = this,
+      _shouldContinue,
+      _result;
+  var _callee = function (n) {
+    if (n <= 0) {
+      return "foo";
+    }
+    try {} finally {
+      _arguments = [n - 1];
+      _this = undefined;
+      return _shouldContinue = true;
+    }
+  };
+
+  do {
+    _shouldContinue = false;
+    _result = _callee.apply(_this, _arguments);
+  } while (_shouldContinue);
+  return _result;
+})(1000000) === "foo";